University:
Western Sydney University
Course:
MEDI 2003 | Clinical Sciences 2
Academic year:

2024
Views:

152

Pages:

2
Author:

Mariam A. A.

Pathology of Mild Hypertension Blood vessels • Arterioles show wall thickening due to “hyaline arteriolosclerosis” • Small arteries show wall thickening: o Intimal proliferation (+ accumulates inflammatory products) o Elastic reduplication o Smooth muscle hypertrophy (+ death at some layers) • Medium and large arteries – Atheroma accelerated + more severe Vascular remodeling • Increases wall to lumen ratio and chronically increases resistance • Intravascular pressure causes an increase in the wall stress, which then stimulates a hypertrophic process leading to an increase in wall thickness and increase arterial stiffness • Normally the pressure is step-downed as it branches to smaller vessels, but in case of hypertension, there is a downstream effect on the small vessels which disrupt the normal circulation → reduces capillary density • Reduced of micro-vessel density by microvascular rarefaction contrinute to hypertension by decreasing the total arteriolar and capillary cross-sectional area • Macrovascular augmentation (hypertrophy and hyperplasia) of smooth muscle increases peripheral resistance Change in autoregulatory set points • Auto regulation becomes ineffective with extremely high blood pressure and this can result in a series of issues in different organs. In hypertensive patients, the set point of the auto regulation is set higher than the normal range. Thus in these patients the aim should be to gradually decrease the set point and blood pressure over time. Heart • Increased left ventricle wall mass (thickness ≥ 20mm) • Concentric left ventricular hypertrophy (asymmetric = congenital) • Coronary atheroma – e.g. cholesterol blockings of coronary artery Kidneys • Macroscopically both kidneys are atrophic (decrease in size/bilateral contracted kidney), with irregular scars. There is a granular subcapsular surface and cortical thinning. This is described as “benign nephrosclerosis”. • Microscopically, there are small cortical infarcts, the glomeruli show focal sclerosis, and afferent arterioles show hyaline sclerosis and small arteries show intimal proliferation and elastic reduplication. Arteries also show fibrosis of the wall with medial hypertrophy. Larger arteries develop atheroma. Brain • • • Arterioles develop hyaline sclerosis and Charcot-Bouchard aneurysms Arteries develop atheroma Basal ganglia and pons show expanded perivascular spaces, small infarcts and haemorrhages Other tissues • Retina develops focal arteriolar narrowing; changes seen by fundoscopy include “exudates" (swollen ischaemic retinal neurones) “copper wiring" and "silver wiring” (increasing wall thickness with narrowing blood column)